[SCSI] libfcoe: Fix section mismatch

Recent changes to add fcoe_sysfs caused libfcoe_init to call fcoe_transport_exit
in a module initialization routine. The change resulted in the below error. This
patch removes the __exit keyword from the fcoe_transport_exit definition such
that it may be called from an __init routine.

WARNING: drivers/scsi/fcoe/libfcoe.o(.init.text+0x21): Section mismatch in reference from the function init_module() to the function .exit.text:fcoe_transp
exit()
The function __init init_module() references
a function __exit fcoe_transport_exit().
This is often seen when error handling in the init function
uses functionality in the exit path.
The fix is often to remove the __exit annotation of
fcoe_transport_exit() so it may be used outside an exit section.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>